arm64: dts: rockchip: Drop edgeble-neu6b dcdc-reg4 regulator-init-microvolt

The 'regulator-init-microvolt' property is not currently supported by
any driver, it was simply carried on from downstream kernels.

rk3588-edgeble-neu6b-io.dtb: pmic@0: regulators:dcdc-reg4: Unevaluated properties are not allowed ('regulator-init-microvolt' was unexpected)

Remove the invalid property.
Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Link: https://lore.kernel.org/r/20231125190522.87607-2-jagan@edgeble.aiSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3588-edgeble-neu6b.dtsi

@@ -165,7 +165,6 @@ vdd_vdenc_s0: vdd_vdenc_mem_s0: dcdc-reg4 {
 				regulator-boot-on;
 				regulator-min-microvolt = <550000>;
 				regulator-max-microvolt = <950000>;
-				regulator-init-microvolt = <750000>;
 				regulator-ramp-delay = <12500>;
 
 				regulator-state-mem {